Advanced containment system

ABSTRACT

A containment system to isolate waste in the ground including parallel interlocking tubes.

RELATED APPLICATION

This application claims priority from United States provisionalapplication Ser. No. 60/169,112 filed Dec. 6, 1999 and is incorporatedby reference.

CONTRACTUAL ORIGIN OF THE INVENTION

This invention was made with United States Government support underContract No. DE-AC07-94ID13223, now Contract No. DE-AC07-99ID13727awarded by the United States Department of Energy. The United StatesGovernment has certain rights in the invention.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to methods and devices for insitu containment of buried waste. More particularly, embodiments of thepresent invention relate to an improved barrier, as well as to itsinstallation and use, for reliably containing and managing leachate fromburied waste.

2. Prior State of the Art

Management and disposal of various types of waste are long-standingproblems. Early waste management and disposal systems were primitive,because there were no disposal or environmental regulations in place atthe time. In countless instances, the waste was simply buriedunderground. The volume of waste that has been buried is tremendous.Some experts estimate that landfills in the United States alone holdmore than 3 million cubic meters of buried waste. Further, much of thewaste that was buried comprises heavy metals such as mercury andcadmium, carcinogenic materials such as trichloroethylene, radioactivematerials, and other hazardous substances.

While burial and similar approaches produced an aesthetically pleasingresult by removing the waste from sight, it was soon discovered thateffluent from the buried waste was working its way through the soil andinto the groundwater. This process is commonly known as leaching.Because groundwater is a major source of water for drinking and foragriculture, contamination of the groundwater by leaching is a majorconcern.

The contamination caused by buried waste is not limited solely togroundwater however. At least some of the groundwater finds its way intowaterways such as streams, rivers, and lakes, thus polluting thosewaterways and poisoning the plant and animal life. Obviously, pollutedwaterways pose a threat to humans as well, particularly in the case ofwaterways and bodies of water used for recreational purposes and/or as asource of drinking water.

Not all of the cases of groundwater pollution arise from the leaching ofchemicals from waste sources. In some cases, the waste is buried in thepath of the groundwater and as groundwater flows through the waste, itcollects various chemicals and toxins from the waste, and deposits thosechemicals and toxins in other soils and waterways.

Clean soil and groundwater are important to human, plant, and animallife as well as to the environment in general. Accordingly, a variety ofmethods and devices have been devised to attempt to resolve the problemsinduced by buried waste. These remedies can be broadly grouped into thecategories of remediation and containment. Remediation remedies focus onprocesses designed to change the chemical composition of a contaminatedmaterial or contaminant, while containment remedies seek to eliminatethe pollution problem by removing or isolating the contaminants andcontaminated material from the surrounding area.

Remediation approaches such as biological treatments, thermal processesand chemical processes are problematic for a variety of reasons. Inparticular, many of these remediation techniques are expensive andpotentially hazardous. Further, it is difficult to verify theeffectiveness of many of the treatments and remediation-type approachesmay not be appropriate for all types of contaminated material. Finally,determining the proper remediation technique is, in itself, a complexand time-consuming process, particularly in view of the web ofregulations and procedures that govern such treatments.

Containment, barrier, or in situ, approaches are problematic as well.One known containment approach is simply to dig up and remove thecontaminated soil for treatment and/or disposal. This approach isexpensive and time-consuming and often accomplishes little more thanmoving the problem to another location. Other containment approachesinvolve installing vertical and/or horizontal barriers around the buriedwaste. In theory, this approach is attractive because it does notinvolve digging up or otherwise disturbing the buried waste.

However, these containment or barrier systems suffer from a variety ofinadequacies including lack of durability, continuity and integrity.These inadequacies are a function of numerous factors including, but notlimited to: exposure to harsh chemicals such as concentrated salinesolutions, and saturated calcite and gypsum solutions; exposure toextreme thermal gradients such as are typically experienced infreeze/thaw zones; and exposure to stresses induced by shifting in theearth.

The hydraulic conductivity, which is the rate at which a fluid orhazardous substance flows through a barrier, is unacceptably high insome barrier systems and other typical barrier systems are notparticularly well-suited to a variety of soil conditions such as hardrock and sand. A further flaw is that many barrier systems do notprovide methods for evaluating the integrity of the barrier during andafter installation, which is complicated by the fact that many barriersystems also lack provision for long term monitoring of the containmentzone and the leachate therefrom. The inability to monitor a barriersystem that is isolating hazardous waste is unacceptable because of thepotential harm that can be caused to the environment. The lack ofdurability, continuity and integrity in known containment systems has asignificant effect on the performance of those systems and theeffectiveness of those containment and barrier systems cannot be readilydetermined or evaluated.

Accordingly, what is needed is an improved in situ containment systemand a method for installing the system. Specifically, the containmentsystem should be durable so as to maintain both integrity andeffectiveness under a variety of physical and thermal conditions as wellas adaptable to wide range of soil types and conditions. The containmentsystem should be chemically stable and impervious to attack by thechemicals, compounds, and microbes typically encountered in buriedwaste. The containment system should also have a low hydraulicconductivity so as to minimize the passage of fluids and chemicalsthrough the barrier and the containment system should monitor theintegrity of the barrier both during and after installation. Further,the containment system should be capable of long-term monitoring of thezone enclosed by the containment system and should also be capable ofmonitoring the leachate from the zone of interest. Also, both the systemand the method for installing the containment system should berelatively simple and cost-effective. Finally, the installation methodshould ensure that the containment system is properly placed andoriented.

OBJECTS AND SUMMARY OF THE INVENTION

The present invention has been developed in response to the currentstate of the art, and in particular, in response to these and otherproblems and needs that have not been fully or completely solved bycurrently available waste containment systems and methods.

Thus, it is an overall object of one embodiment of the present inventionto provide a simple yet cost-effective waste containment system that isparticularly useful for in situ monitoring, control, and management ofburied waste and associated leachate.

It is another object of one embodiment of the invention to provide acontainment system including one or more barriers comprised ofinterlocking steel casing sections so as to facilitate a durable,impervious and chemically stable containment system having a high degreeof continuity and integrity.

A further object of one embodiment of the present invention is to impartadded integrity and durability to the barrier by filling the metalliccasing sections with an impervious material.

Another object of one embodiment of the present invention is to providea containment system that employs embedded sensors for long-termmonitoring of the integrity of the barriers and for monitoring thecontainment zone and leachate.

It is also an object of one embodiment of the present invention toprovide a containment system installation method that is cost-effective.

Finally, it is an object of one embodiment of the present invention toprovide a containment system installation method which will ensureaccurate placement and orientation of the containment system.

The effects of buried waste on the environment can be quite profound andare not limited to the area in which the buried waste is located becausechemicals, toxins and other hazardous substances associated or producedby the buried waste are frequently introduced into the groundwater andcarried to other parts of the environment. These chemicals and otherdangerous substances may ultimately be found in drinking water,irrigation water, rivers, lakes, and other sources of water. In thismanner, buried waste has an adverse effect on the health of people,plants, and animals and also harms the environment.

In many instances, the buried waste is difficult to move and relocationof the buried waste may actually cause more harm. In these and otherinstances, it is desirable to contain the buried waste by surroundingthe buried waste with a barrier that effectively isolates the buriedwaste. The containment systems and barriers of the present inventionprovide an advanced containment system that is continuous, durable, andcapable of performing in a variety of geologic and environmentalconditions. Additionally, the effectiveness of the advanced containmentsystem is able to be verified over a sustained time period.

In a preferred embodiment, the containment system includes one or morebarriers comprising a plurality of metal casing sections longitudinallyconnected by interlocking structure present on each casing. The barrierscooperate with one or more concrete walls to collectively enclose atleast a portion of the buried waste.

Preferably, a barrier is first installed underneath the zone ofinterest. Specifically, a line of individual steel casing sections areplaced by a micro-tunneling device or the like which simultaneouslyexcavates a tunnel and installs connecting casing segments behind themicro-tunneling device as tunneling progresses. The length of thetunnels is determined by the size of the zone of interest to becontained. Preferably, the tunneling device includes a system forensuring accurate placement and orientation of the tunnels and casingsections. As each tunnel is dug and lined with casing sections, asuccessive adjacent tunnel is dug and casing sections situated thereinwhich longitudinally interlock with the casing sections placed in thepreviously excavated tunnel, so as to form a continuous barrier ofpredetermined width.

The casing sections and the joints whereby they interlock are preferablyfilled with grout or the like so as to provide an added measure ofstrength, durability, and imperviousness to the barrier. In a preferredembodiment, two vertical barriers are interlocked with the ends of thehorizontal barrier so that the horizontal barrier and vertical barrierscollectively form a continuous U or channel-shaped containment boundaryaround the zone of interest. Preferably, the horizontal and/or verticalbarriers include sensors installed contemporaneously so as to permitmonitoring of the integrity and performance of the barriers during andafter installation. In a preferred embodiment, the barriers also includesensors for long-term monitoring of the zone of interest and associatedleachate.

After the channel has been completed, a concrete wall is installed ateither end of the containment area, thereby cooperating with thebarriers to enclose the containment area on all sides except the top.Optionally, at least one of the barriers has one or more openings influid communication with a collection system or the like so thatleachate flowing through the opening can be monitored, collected, andprocessed.

Additional objects and advantages of the present invention will be setforth in the description which follows, and in part will be obvious fromthe description, or may be learned by the practice of the invention. Theobjects and advantages of the invention may be realized and obtained bymeans of the instruments and combinations particularly pointed out inthe appended claims. These and other objects and features of the presentinvention will become more fully apparent from the following descriptionand appended claims, or may be learned by the practice of the inventionas set forth hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more fully understand the manner in which the above-recitedand other advantages and objects of the invention are obtained, a moreparticular description of the invention will be rendered by reference tospecific embodiments thereof which are illustrated in the appendeddrawings. Understanding that these drawings depict only typicalembodiments of the invention and are not therefore to be considered tobe limiting of its scope, the invention and its presently understoodbest mode for making and using the same will be described and explainedwith additional specificity and detail through the use of theaccompanying drawings in which:

FIG. 1 is a perspective view of a micro tunneling device installingcasing sections underneath the zone of interest;

FIG. 1A illustrates a cross-section view of one embodiment ofsimultaneous double tunnel excavation, looking towards the front end ofthe tunnels, and indicates the interconnection between adjacent tunnels;

FIG. 1B illustrates a cross-section view of one embodiment ofsimultaneous triple tunnel excavation, looking toward the front end ofthe tunnels, and indicates the interconnection between adjacent tunnels;

FIG. 1C illustrates a cross-section view of one embodiment of theinterlock structure between adjacent casing sections;

FIG. 2 is a perspective view of an embodiment of the installedcontainment system;

FIG. 3 is a depiction of an embodiment of a barrier adapted for leachatecollection and processing; and

FIG. 4 is a schematic of a casing section having a plurality of sensorsfor monitoring the zone of interest and the barrier.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The threat to the environment produced by buried waste begins when thecontaminants produced by buried waste leach into the groundwater. Oncegroundwater has been contaminated, the potential harm is great, becausegroundwater typically makes its way to rivers and lakes, which arefrequently sources of drinking water and irrigation water. In thismanner, the contaminants originally produced by buried waste make theirway to plants, animals and humans.

The advanced containment system (ACS) of the present invention addressesthese and other concerns of buried waste by isolating a zone ofinterest, which provides several significant advantages. The ACS iscapable of creating a continuous barrier of various sizes andconfigurations. The barriers can be installed in both saturated andunsaturated zones of interest and in a variety of geologies from softsoil to hard rock. ACS provides for the verification of the barrierinstallation as well as structural continuity of the barrier. ACS alsosignificantly improves the hydraulic performance of the barrier, allowsthe performance of the barrier to be monitored for an extended period oftime, and is cost effective.

As used herein, “buried waste” refers to: construction and demolitionmaterials such as lumber and concrete blocks; laboratory equipment suchas glassware and tubing; process equipment such as valves, ion exchangeresins, and heat exchangers; maintenance equipment such as oils andgreases; decontamination materials such as paper, rags and plastics;hazardous and radioactive materials; and any other type of waste orgarbage which is buried in the ground. The chemicals and othersubstances produced by buried waste which leaches into the surroundingsoil and groundwater are also encompassed by the term buried waste.“Zone of interest” refers to an area or volume of ground containingburied waste. A containment system is typically designed to isolate thezone of interest from the surrounding earth and water such that theburied waste and associated leachate is geographically confined to thezone of interest.

The present invention is described in terms of diagrams and figures.Using the diagrams and figures in this manner to present the inventionshould not be construed as limiting its scope. Rather, the diagrams andfigures are intended to be exemplary embodiments of the presentinvention. Additionally, the diagrams and figures are not necessarilydrawn to scale.

In general, the present invention relates to advanced containmentsystems for use in in situ monitoring, controlling, and management ofburied waste and associated leachate. FIGS. 1 through 4 indicate variouspresently preferred embodiments of an advanced containment system. Otherembodiments of the present invention may also be available and suchfigures are not intended to be limiting.

FIG. 1 depicts a zone of interest 100 to be isolated by a containmentsystem. In order to contain zone of interest 100, a trench 200 is firstdug on either side of zone of interest 100 (only one trench is shown)containing buried waste 102. Micro tunneling device 300 is then placedin trench 200. Trench 200 facilitates the introduction of microtunneling device 300, but the creation of trench 200 may be omitted insome embodiments. If trench 200 is dug, the soil, if contaminated, isdisposed of by appropriate and approved methods. Additionally, any soilexcavated by tunneling device 300 is also collected, scanned, anddisposed of by similar methods.

One type of micro tunneling device 300 is known as a micro tunnel boringmachine, or micro TBM. In a preferred embodiment, micro tunneling device300 comprises an auger head 302 or the like for rotary excavation ofsoil 104. However, it is contemplated that the inventive barrier systemmay be installed in any of a number of different types of soil and rock,or combinations thereof. Accordingly, installation of the containment orbarrier system by other excavation devices including, but not limitedto, ‘double-tube down the hole’ drills (preferred for hard soil and softrock), rotary percussion drills (preferred for hard rock), Multi-faceTunnel Boring Machine, Multi-face Shielded Tunnel Boring Machine,Shielded Tunnel Boring Machine coupled with a Horizonal Cutting ScrewAuger, Pipe Propulsion, Curved Pipe Propulsion, Trench Cutting, and thelike is contemplated as being within the scope of this invention.Preferred construction speeds are about 8 meters/day of tunnel throughsoft soil, about 5 25 meters/day of tunnel through hard soil/soft rock,and about 8 meters/day of tunnel through hard rock.

In order to contain the buried waste in a zone of interest, microtunneling device 300 serially drills a plurality of parallel tunnelsunderneath the zone of interest. Preferably, each tunnel issubstantially circular in cross-section. However, this inventioncontemplates as within its scope tunnels of a wide variety of differentcross sectional shapes. Each tunnel begins in trench 200 and ends intrench 200 (not shown) on the other side of zone of interest 100. Microtunneling device 300 lines each tunnel with casing sections 400 so as toform a tube 401 inside each tunnel as drilling progresses. One of thefunctions of casing sections 400 installed during tunneling is tosupport the portion of the tunnel already drilled. In a physicallysupportive matrix such as hard rock, casing sections 400 may not berequired. In a preferred embodiment, casing sections 400 comprise a body403 optimally constructed of steel or the like. However, alternativecasing materials that would provide the functionality and durability ofsteel are contemplated as being within the scope of this invention.Alternative casing materials include, but are not limited to, concreteand the like.

In a preferred embodiment, each tunnel is about 0.5 meters in diameter.Further, it is preferred that the tunnels be in the range of about 50meters to about 150 meters long.

An alternative embodiment is depicted in steps (i) through (vi) of FIG.1A. In this embodiment, two parallel overlapping tunnels 250A and 250B,respectively, are excavated substantially simultaneously (step (i)) bymicro tunneling device 300 (not shown). Overlapping tunnels 250A and250B are preferably substantially circular in cross-section. However,this invention contemplates as within its scope tunnels of a widevariety of different cross sectional shapes. Micro tunneling device 300preferably comprises a double multiface TBM or the like. As excavationprogresses, overlapping tunnel 250A is substantially filled with barrierfiller 252 (step (ii)). Barrier filler 252 preferably comprises grout,cement, concrete, bentonite-based materials, modified cement,polysiloxane, acrylic polymers, or the like. Substantiallysimultaneously with excavation of overlapping tunnels 250A and 250B, andbackfilling of overlapping tunnel 250A, barrier filler forms 254 areplaced in overlapping tunnel 250B and barrier filler 252 is poured orinjected about barrier filler forms 254 as indicated in FIG. 1A (step(ii)) so as to form a hollow tube made of barrier filler 252. Afteroverlapping tunnel 250B has been completely excavated, it is backfilledwith barrier filler 252 (step (iii)). The process then is then repeated,a portion of overlapping tunnel 250B being cut out (see FIG. 1A) as partof the excavation of overlapping tunnel 250A′ and the excavationsequence is repeated as required (steps (iv) through (vi)). In thisalternative embodiment, no casing sections 400 are required.

Yet another alternative embodiment is depicted in steps (i) through (vi)of FIG. 1B. In this embodiment, three parallel overlapping tunnels 250C,250D, and 250E, respectively, are excavated substantially simultaneouslyby a tunneling device (not shown) such as a triple multiface shieldmachine or the like. Alternatively, the tunneling device (not shown)comprises two shielded TBMs having a horizontal slot/auger cutterpositioned therebetween so as to reduce the volume of excavated soil andthe amount of barrier filler 252 subsequently required for filling.Overlapping tunnels 250C, 250D, and 250E are preferably substantiallycircular in cross-section. However, this invention contemplates aswithin its scope tunnels of a wide variety of different cross sectionalshapes.

As excavation progresses, overlapping tunnels 250C and 250E aresubstantially filled with barrier filler 252. Substantiallysimultaneously with excavation of overlapping tunnels 250C, 250D and250E, and backfilling of overlapping tunnels 250C and 250E, barrierfiller forms 254′ are placed in overlapping tunnel 250D and barrierfiller 252 is poured or injected about barrier filler forms 254′ asindicated in step (ii) of FIG. 1B. After overlapping tunnel 250D hasbeen completely excavated, it is backfilled with barrier filler 252 asindicated in step (iii) of FIG. 1C. Alternatively, tunnel 250D may beleft open. As indicated in steps (iv) through (vi) of FIG. 1B, theprocess then is then repeated, a portion of overlapping tunnel 250Ebeing cut out as part of excavation of overlapping tunnel 250C′ and theexcavation sequence repeated as required. In this alternativeembodiment, no casing sections 400 are required.

With continuing reference now to FIG. 1, micro tunneling device 300preferably includes a control system (not shown) for ensuring accuratedrilling. Alignment and orientation of the first tunnel drilled iscritical as all subsequent tunnels are drilled with reference to thefirst tunnel. In particular, as subsequent tunnels are drilled and linedwith casing sections 400, each casing section 400 installed in asubsequently drilled tunnel is longitudinally interlocked with anadjacent casing section 400 in the previously drilled and lined tunnelso that a continuous barrier segment 500A is formed as indicated in FIG.1. In a preferred embodiment, barrier segment 500A is substantiallyhorizontal.

One embodiment of complementary interlocking structure 402A and 402Badapted to interlock adjacent casing sections 400 is indicated in FIG.1C. Complementary interlocking structure 402A and 402B provides the dualbenefit of positively interlocking adjacent casing sections 400 and,once the first tunnel is drilled and lined with casing sections 400,complementary interlocking structure 402B serves to accurately andreliably guide complementary interlocking structure 402A of adjacentcasing sections 400 into place, thus ensuring accurate placement andorientation of those casing sections 400 and thus of barrier segment500A as a whole. Note that complementary interlocking structure 402A and402B represents only one possible embodiment of structure in accordancewith the teachings of this invention, and this invention is notconsidered to be limited thereto. It is contemplated that any of a widevariety of structural arrangements could profitably be employed toachieve the functionality of complementary interlocking structure 402Aand 402B and, accordingly, those structural arrangements arecontemplated as being within the scope of the present invention as well.Two possible alternative interlock arrangements, previously discussed,are indicated in FIGS. 1A and 1B, respectively.

Once barrier segment 500A is installed, barrier segments 500C and 500Bare installed in like manner by micro tunneling device 300 (not shown)to produce the U-shaped configuration indicated in FIG. 2. Inparticular, barrier segment 500B interlocks with barrier segment 500A atedge casing 502, by way of complementary interlocking structure 402A and402B, and excavation and lining of subsequent tunnels proceedssubstantially vertically upward from edge casing 502 until barriersegment 500B reaches a desired height. In similar fashion, barriersegment 500C employs complementary interlocking structure 402A or thelike to interlock with complementary interlocking structure 402B or thelike on barrier segment 500A at edge casing 504, the excavation andlining of subsequent tunnels proceeding vertically upward from edgecasing 504 until barrier segment 500C reaches a desired height. Notethat while a preferred embodiment indicates a substantially U-shapedbarrier 500 formed by three barrier segments 500A, 500B, and 500C, thisinvention contemplates as within its scope other barriers having thesame functionality as the U-shape including, but not limited to, aV-shaped configuration.

Upon installation of barrier segments 500A, 500B, and 500C, casingsections 400 and interlock spaces 404 are preferably filled with abarrier filler 252 such as grout, cement, concrete, bentonite-basedmaterials, modified cement, polysiloxane, acrylic polymers, or the like,as indicated in FIG. 2. When filled, interlock spaces 404 provide aconnection having the same integrity, performance and functionality ascasing sections 400 when casing sections 400 are filled. Barrier filler252 thus cooperates with steel casing sections 400 to produce a barrier500 that is chemically stable, even when exposed to solutions saturatedwith calcite, gypsum, and the like. Further, barrier 500 has a highdegree of continuity, and resists attack by chemicals, microbes, and thelike. Additionally, resulting barrier 500 has a low hydraulicconductivity K, preferably, K≦10⁻⁷ cm/sec, so that barrier 500 issubstantially impermeable by leachate 106 generated by buried waste 102.Finally, resulting barrier 500 is thermally stable and retains itsintegrity and effectiveness under a wide variety of physical and thermalconditions including ground shifting, and large temperature gradients.Barrier 500 is particularly well-suited for use in freeze/thawconditions and conditions where heavy precipitation causes high levelsof groundwater flow.

Note that a variety of means may be profitably employed to perform thefunctions, enumerated herein, of barrier segments 500A, 500B and 500C.Barrier segments 500A, 500B, and 500C are examples of barrier means forlimiting migration of leachate and for containing buried waste in a zoneof interest. Accordingly, the structure disclosed herein simplyrepresents one embodiment of structure capable of performing thesefunctions. It should be understood that this structure is presentedsolely by way of example and should not be construed as limiting thescope of the present invention in any way.

Once barrier segments 500A, 500B, and 500C have been installed andfilled with barrier filler 252, concrete walls 600 (one wall shownremoved for clarity) are installed and positioned in trench 200 (onetrench shown removed for clarity) so as to abut barrier segments 500A,500B, and 500C, as indicated in FIG. 2. Thus, walls 600 cooperate withbarrier 500 to form a containment system that substantially containszone of interest 100 and prevents buried waste 102 and associatedleachate 106 from escaping from zone of interest 100.

Walls 600 preferably comprise concrete, grout, bentonite-basedmaterials, or the like. In an alternative embodiment, only barriersegment 500A (FIGS. 1 and 2) is installed, and walls 600 (FIG. 2) areinstalled in place of barrier segments 500B and 500C. Alternatively,barrier segment 500A is curved such that the ends extend above the zoneof interest, in which case the need for walls 600 is obviated. Thisinvention further contemplates as within its scope a variety ofcombinations and arrangements of barrier segments and walls including,but not limited to, those combinations and arrangements discussedherein.

In an alternative embodiment, illustrated in FIG. 3, barrier segment500A is configured to facilitate collection and processing of leachate106 produced by buried waste 102. In particular, at least some casingsections 400 are left unfilled, i.e., not filled with barrier filler252, and are perforated with holes 508 collectively forming an openingor ‘window’ so as to permit leachate 106 to flow down into casingsections 400 where it can be collected and routed to an accumulationtank 700 or the like for holding and subsequent processing by processingsystem 800. In a preferred embodiment, accumulation tank 700 includessensors 702 or the like for monitoring various parameters including, butnot limited to, leachate accumulation levels. In a preferred embodiment,processing system 800 analyzes and/or processes, by any of a variety ofwell known methods, said leachate to extract chemicals, minerals,metals, and other desired material. Such known methods contemplated asbeing within the scope of the present invention include, but are notlimited to, filtration and the like.

Finally, a critical feature of the inventive containment system is theability to monitor the integrity and performance of the containmentsystem. The monitoring system also has a predictive capacity whichallows it to predict potential problem areas and failures in thecontainment system. Additionally, the monitoring system of the presentinvention detects emissions and flow of leachate 106 from zone ofinterest 100. Monitoring of leachate 106 and other emissions isimportant because, among other things, it permits site operators toevaluate the condition and composition of zone of interest 100.

As indicated in FIG. 4, a ‘smart’ casing section 400A is contemplatedthat incorporates a variety of embedded sensors for performing theaforementioned functions. As used herein, ‘embedded sensors’ refer tothose sensors located either internal to casing sections 400A, and/orlocated on the exterior surface 408 of casing sections 400A. A preferredembodiment of smart casing section 400A contemplates both internal andexternal sensors. With reference first to external sensors,presence/concentration sensor 406 is recessed in exterior surface 408 ofsmart casing section 400A and measures both the types and concentrationof contaminants 108, whether present in leachate 106 or in soil 104. Insimilar fashion, distribution sensor 410 is recessed in exterior surface408 of smart casing section 400A and measures the spatial distributionof contaminants 108 and/or leachate 106 in soil 104. Likewise, radiationdetection and measurement (‘RDM’) sensor 412 is recessed in exteriorsurface 408 of smart casing section 400A and monitors and reportsradiological activity in zone of interest 100. In a preferredembodiment, presence/concentration sensor 406, distribution sensor 410,and RDM sensor 412 are installed on smart casing section 400A inlocations remote from complementary interlocking structure 402A and402B.

In addition to their respective sensing functions,presence/concentration sensor 406, distribution sensor 410, and RDMsensor 412 are configured to feed data to real-time data managementsystem 414 for processing and analysis. Preferably, real-time datamanagement system 414 comprises a computer-based application thatintegrates hardware, software, sensor output, positioning informationand data analysis functions.

A variety of different sensor types are contemplated as being suitablefor performing the functions of presence/concentration sensor 406,distribution sensor 410, and RDM sensor 412. In particular, the functionof presence/concentration sensor 406 is preferably performed by asurface acoustic wave (SAW) sensor or solid state sensor such as a fieldeffect transistor (FET), as well as by Fourier transform infraredspectrometry (FTIR), time domain electromagnetics, or the like. Timedomain electromagnetics, which measure presence, location, andconcentration of contaminants by measuring conductivity and dielectriccontrasts of the medium in which they are located, are also suitable forperforming the spatial distribution measurement function of distributionsensor 410. The radiation detection and measurement functions of RDMsensor 412 is preferably performed by gamma-ray spectrometry, plasticscintillators, scintillating fibers, miniature chamber detectors, or thelike. Note that this invention contemplates as within its scope variousother types of sensors that will provide the functionality describedherein.

As indicated in FIG. 4, smart casing section 400A also includes avariety of internal sensors for performing a number of differentfunctions relating to the integrity of smart casing section 400A.Because these sensors are internal to smart casing section 400A, theypermit monitoring of various aspects of the installation while theinstallation is in progress. In view of the fact that the joints betweensuccessive smart casing sections 400A represent a potential leak-throughpath for leachate 106 and contaminants 108, the integrity of thosejoints is of particular concern. Accordingly, joint integrity sensor 418evaluates the integrity of the joint between successive smart casingsections 400A. That is, joint integrity sensor 418 determines whetherthere are cracks, voids, or other defects in the joint that could permitleak through of leachate 106 and/or contaminants 108, and jointintegrity sensor 418 also detects the onset and growth of cracks andvoids. As with presence/concentration sensor 406, distribution sensor410, and RDM sensor 412, joint integrity sensor 418 is configured tofeed data to real-time data management system 414 for processing andanalysis.

Joint integrity can be evaluated in several different ways. Preferredsensors for performing this function include acoustic/ultrasonic timedomain reflectometry sensors that detect cracks and large voids instructures such as smart casing section 400A. Also, known optical fibersensors employ fiber optic principles to make strain measurements insmart casing section 400A and thereby detect the onset and growth ofvoids and cracks in smart casing section 400A. Because joint integritycan be meaningfully evaluated in a variety of different ways, thisinvention contemplates as within its scope any sensor type that would besuitable for directly or indirectly measuring and evaluating jointintegrity. Note also that the aforementioned sensor types are equallysuitable for evaluating the integrity of the structure of smart casingsection 400A itself, that is, they are not limited solely to jointintegrity applications.

In addition to containing sensors for evaluating smart casing section400A structure and joint integrity, smart casing section 400A of theinventive barrier also includes migration sensor 420 for detectingmigration and leakage of leachate 106 and contaminants 108. In apreferred embodiment, migration sensor 420 comprises a sensorincorporating fiber optic coupled optical spectroscopy functionality formeasuring, for example, volatile organic compounds (VOCs) that may haveleaked through smart casing section 400A of the inventive barrier.However other migration sensors suitable for measuring chemicalmigration, and emission of VOCs and the like are contemplated as beingwithin the scope of the present invention. As indicated in FIG. 4,migration sensor 420 is preferably configured to feed data to real-timedata management system 414 for processing and analysis.

A preferred embodiment of smart casing section 400A also includes one ormore predictive sensors 422 for identifying failure precursors inbarrier filler 252 and/or in smart casing section 400A. One preferredpredictive sensor 422 is one that measures changes in the dielectricpermeability and/or permittivity of barrier filler 252. Changes indielectric permeability and/or permittivity are typically precursors tomacroscopic changes in performance of barrier filler 252, and thus ofthe containment system as a whole. In an alternative embodiment,predictive sensor 422 comprises electrical source and antenna arrays(not shown) used to measure changes in resistivity of barrier filler252. A change in resistivity from a baseline measurement taken atinstallation would indicate a break or pocket in barrier filler 252.

Predictive sensors 422 preferably also comprise a sacrificial cathode orthe like for detecting conduction paths through smart casing section400A. Existence of a conduction path through smart casing section 400Aindicates that a failure of smart casing section 400A will ultimatelyoccur. Because galvanic action only occurs when there is a conductionpath, galvanic action at the sacrificial cathode serves to predictfailure of smart casing section 400A. As indicated in FIG. 4, predictivesensors 422 are preferably configured to feed data to real-time datamanagement system 414 for processing and analysis. Note that thisinvention contemplates as within its scope any sensor having analogouspredictive capabilities, and this invention should accordingly not beconstrued to be limited to those embodiments enumerated and discussedherein.

The containment system also provides the benefit of a barrier havingmultiple layers. In the instance of metal casings filled with concreteor other suitable material, at least three layers of containment areprovided. The first layer comprises the top portions of the casings. Thesecond layer comprises the concrete or other suitable material whichfills the casings as well as the interlock structures. In addition toproviding a second layer of containment, the concrete further enhancesthe strength of the barrier. The third layer comprises the bottomportions of the casings. The sensors which are indicative of theintegrity and continuity of the first layer can also be applied to thesecond and third layers. The resulting barrier is continuous, durable,verifiable and may be instrumented to effectively measure its long-termintegrity and performance.

The present invention has been described in terms of buried waste, butthe systems and methods of the present invention have otherapplications. For instance, a barrier having perforated casings may beusing in mining operations to collect the material being mined. When thecollection of the mined material reaches a predetermined level, it iseasily extracted from collectors in the perforated casings. Otherapplications include perforated barriers used for agricultural purposes.For example, the water used to irrigate an agricultural area typicallydrains in a particular location. A containment barrier having perforatedcasings can be installed in the drainage area. The smart casings may besupplied with modules that function to remove contaminants such asfertilizer and pesticide from the irrigation water.

The present invention may be embodied in other specific forms withoutdeparting from its spirit or essential characteristics. The describedembodiments are to be considered in all respects only as illustrativeand not restrictive. The scope of the invention is, therefore, indicatedby the appended claims rather than by the foregoing description. Allchanges that come within the meaning and range of equivalency of theclaims are to be embraced within their scope.

We claim:
 1. A containment system for containing a zone of interest,said containment system comprising: a plurality of substantiallyparallel tubes, each of said plurality of substantially parallel tubesadjoining at least one other substantially parallel tube so that saidplurality of substantially parallel tubes collectively forms acontinuous barrier of pre-determined configuration; barrier fillersubstantially filling each of said plurality of substantially paralleltubes; and a plurality of walls, said plurality of walls cooperatingwith said continuous barrier to substantially contain the zone ofinterest.
 2. The containment system according to claim 1, wherein saidplurality of substantially parallel tubes comprise tunnels, each of saidtunnels partly intersecting at least one other tunnel.
 3. Thecontainment system according to claim 1, wherein each of said pluralityof substantially parallel tubes comprises a guide structure for guidingat least one adjacent substantially parallel tube into position.
 4. Thecontainment system according to claim 3, wherein said guide structurecomprises complementary interlocking structure, the complementaryinterlocking structure of a first substantially parallel tubecooperating with corresponding complementary interlocking structure of asecond substantially parallel tube so as to guide said secondsubstantially parallel tube into position.
 5. The containment systemaccording to claim 1, wherein each of said plurality of substantiallyparallel tubes comprises a plurality of casing sections.
 6. Thecontainment system according to claim 5, wherein said plurality ofcasing sections comprise steel.
 7. The containment system according toclaim 1, wherein each of said plurality of substantially parallel tubescomprises complementary interlocking structure so that saidsubstantially parallel tubes are interlocked with each other, saidbarrier filler substantially filling interlock spaces formed when saidsubstantially parallel tubes are interlocked.
 8. The containment systemaccording to claim 1, wherein said pre-determined configurationcomprises a substantially horizontal plane located underneath the zoneof interest.
 9. The containment system according to claim 8, whereinsaid plurality of walls comprises four walls, each wall beingsubstantially perpendicular and adjacent to a corresponding edge of saidcontinuous barrier so that said walls cooperate with said continuousbarrier to substantially contain the zone of interest.
 10. Thecontainment system according to claim 1, wherein said pre-determinedconfiguration substantially comprises an open-ended channel, and saidplurality of walls comprises two walls, each wall being adjacent to anend of said open-ended channel so that said plurality of walls cooperatewith said continuous barrier to substantially contain the zone ofinterest.
 11. The containment system according to claim 1, furthercomprising a plurality of sensors embedded in said plurality ofsubstantially parallel tubes, wherein said plurality of sensors are inoperative communication with a real-time data management system.
 12. Thecontainment system according to claim 1, wherein said barrier fillercomprises at least one of: grout; cement; concrete; bentonite-basedmaterial; modified cement; polysiloxane; and acrylic polymers.
 13. Thecontainment system according to claim 1, wherein said continuous barrierdefines at least one opening, and a leachate flows from the zone ofinterest through said continuous barrier via said opening.
 14. A wastemanagement system for containing a zone of interest, comprising: aplurality of parallel tubes connected to each other to collectively forma barrier of pre-determined configuration, said barrier defining atleast one opening; barrier filler substantially filling said barrier; aplurality of walls, said plurality of walls cooperating with saidbarrier to substantially contain the zone of interest; a leachatecollection system for collecting leachate from the zone of interest,said leachate collection system in fluid communication with said atleast one opening of said barrier; and a monitoring system, saidmonitoring system configured for monitoring at least said barrier andthe zone of interest.
 15. The waste management system according to claim14, wherein said monitoring system comprises at least a first set andsecond set of sensors in operative communication with a real-time datamanagement system.
 16. The waste management system according to claim15, wherein said first set of sensors is configured to monitor the zoneof interest and said second set of sensors is configured to monitor saidbarrier.
 17. The waste management system according to claim 16, whereinsaid first set of sensors comprises a presence/concentration sensor, aradiation detection and measurement sensor, and a distribution sensor.18. The waste management system according to claim 16, wherein saidsecond set of sensors comprises a joint integrity sensor, a migrationsensor, and a predictive sensor.
 19. The waste management systemaccording to claim 14, wherein said monitoring system additionallymonitors said plurality of walls.
 20. The waste management systemaccording to claim 14, wherein said leachate collection system comprisesan accumulation tank and associated piping.
 21. The waste managementsystem according to claim 20, further comprising a leachate processingsystem for evaluating and processing said leachate, said leachateprocessing system being in fluid communication with said accumulationtank.
 22. A containment barrier to facilitate management of leachateflow from a zone of interest, comprising: a plurality of substantiallyparallel tubes, each tube of the plurality being laterally interlockedto at least one other tube along their respective lengths tocollectively form a barrier segment adjacent to the zone of interest; aleachate flow system for managing flow of said leachate through saidbarrier segment, said leachate flow system disposed in said barriersegment; and a barrier filler substantially filling said barriersegment.
 23. The containment barrier according to claim 22, wherein saidleachate flow system comprises at least one of said plurality ofsubstantially parallel tubes defining at least one void, said at leastone void being in fluid communication with the zone of interest, saidleachate flowing from the zone of interest into said at least one void.24. The containment barrier according to claim 23, further defining atleast one outlet in fluid communication with said at least one void. 25.The containment barrier according to claim 24, wherein said outlet isconfigured to allow at least a portion of said leachate to selectivelyflow from said at least one void through said outlet.
 26. Thecontainment barrier according to claim 23, further comprising at leastone filter interposed between the zone of interest and said at least onevoid.
 27. The containment barrier according to claim 22, wherein saidleachate flow system comprises at least one perforated portion of atleast one of said plurality of substantially parallel tubes, said atleast one perforated portion defining at least one void, and saidleachate flowing from the zone of interest through said perforatedportion into said at least one void.
 28. The containment barrieraccording to claim 22, further comprising a monitoring system comprisingat least one sensor carried by at least one tube of said substantiallyparallel plurality of tubes for monitoring at least one of the zone ofinterest and said leachate flow system.
 29. The containment barrieraccording to claim 28, wherein said monitoring system comprises at leastone sensor in operative communication with a real-time data managementsystem.
 30. The containment barrier according to claim 22, wherein eachof said plurality of substantially parallel tubes comprises a pluralityof casing sections.
 31. The containment barrier according to claim 30,wherein said plurality of casing sections comprise steel.
 32. Thecontainment system according to claim 22, wherein said barrier fillercomprises at least one of: grout; cement; concrete; bentonite-basedmaterial; modified cement; polysiloxane; and acrylic polymers.
 33. Acontainment system for containing a zone of interest, the containmentsystem comprising: a barrier for controlling migration of leachate fromthe zone of interest, said barrier comprising a plurality ofsubstantially parallel tubes, each tube at least indirectly connected toat least one other tube of said plurality to form a continuous barrier;and a plurality of walls, said plurality of walls being formedseparately from said barrier and cooperating with said barrier tosubstantially contain the zone of interest.
 34. The containment systemaccording to claim 33, wherein each of said plurality of substantiallyparallel tubes is substantially filled with a barrier filler.
 35. Thecontainment system according to claim 34, wherein each of said pluralityof connected substantially parallel tubes comprises a plurality ofcasing sections.
 36. The containment system according to claim 35,wherein said plurality of casing sections comprise steel.
 37. Thecontainment system according to claim 34, further comprising amonitoring system comprising at least one sensor carried by at least onetube of said plurality of substantially parallel tubes for monitoring atleast one of the zone of interest and said barrier.
 38. The containmentsystem according to claim 33, wherein said plurality of walls comprisesa plurality of connected tubes, wherein said plurality of walls arecontinuously connected with said barrier.